The shipbroking giant said the business remains "robust", but that the Clarksea index - which indicates daily charter rates - was 30 per cent lower in the first half of 2016 compared to the same period last year.

The Baltic Dry Index, based on reports of charters from London shipbrokers, has also tumbled year-on-year, and was "testing all-time lows during the first quarter of 2016", Clarkson said.

The FTSE 250 group said: "Whilst recent strengthening of the US dollar against sterling, if sustained, will offer some limited enhancement to reported profits, the board nevertheless now anticipates that as a consequence of the challenges referred to above profits for 2016 will be materially lower than the fully year 2015."